Ecological patterns 1 Match the words below with

Ecological patterns

1. Match the words below with the numbered arrows 2. 6. 5. Population Biotic factors Ecosystem Community Abiotic factors Organism 4. 3.

The ecological pattern we are studying is the distribution of species along the rocky sea shore from the high tide mark to the low tide mark. This pattern is called inter-tidal zonation

What is Intertidal Zonation?

Zonation: Is a distribution pattern of organisms that occurs in response to both and factors which act together to create an ecosystem that is divided into different horizontal of habitation.

Intertidal zonation In general, species' lower tide height limits are set by species interactions whereas their upper limits are set by climate variables.

Robert Paine Experiment A classic study by Robert Paine showed just that! It involved looking at the relationship between the sea star, Pisaster ochraceous, and the mussel, Mytilus californicus. What is the relationship between these two organisms? >> Predator (Seastar)- Prey (Mussel) >> Exploitation relationship

Normally, these two different species live in a harmonious balance in their intertidal community. To understand the relationship between Pisaster and Mytilus, Paine removed Pisaster from some plots (experimental plot) and allowed them to remain in others (control plot).

• When Sea star (Pisaster) predators are removed, mussel beds extended to lower tide heights (proving that the mussels' lower limits of habitation are set by sea star predation). • Due to mussels inhabiting the lower shore, resident seaweeds were smothered, thus reducing the number of species present on the shore. • Conversely, in the presence of sea stars, mussels' lower limits occur at a tide height at which sea stars are unable to tolerate climate conditions.

A similar thing was happening with the Chthamalus and Balanus barnacles in the zonation video! Read the following handout and use the information and your understanding of ecological patterns and relationships to answer the question: